Tim Johnston has an interesting take on Terry Riley's In C. I don't think I agree with his suggestion that a V7 chord is heard when the F gains some prominance. This is only possible if the listener is actively trying to put a harmonic progression to the piece, and even then the progression is ill-fitted to the music. The F does introduce some dissonance, which could be thought of as a move towards a cadence with the resolution of the dissonance. But this dissonance is not of a standard dominant feel, even a dominant feel over a pedal tone. Call it a dissonant extension, or the introduction of a non-chord-tone, or a Hindemith-ian change of chord series with the half-step dissonance between the E and F.
I do agree that the piece is more than just an interesting concept, and one that can be performed quite musically. A friend performed it with 20 players at her graduate recital at Eastman in 1997. It was a great conclusion, the final notes ringing in the hall and in our ears.